Question

我正在尝试建立数据库连接并检查表中的现有数据。但是我收到了这个错误，我无法找到原因：

警告：mysqli :: query（）：无法获取mysqli    /usr/share/nginx/www/me/container/class_lib.php 在线    33

警告：mysql_fetch_assoc（）预计   参数1为资源，null为给定    /usr/share/nginx/www/me/container/class_lib.php 在线    97

class dbHandler {

    static $dbObj          = null;
    protected $db_host     = 'localhost';       #db host
    protected $db_username = 'user';  #db username
    protected $db_password = 'password';        #db password
    protected $db_name     = 'db';  #db name

    function __construct()
    {
        # connect if not connected
        if(self::$dbObj === null)
        {
            self::$dbObj = new mysqli($this->db_host, $this->db_username, $this->db_password, $this->db_name)
            or die($this->dbObj->error);
        }

        mysqli_set_charset(self::$dbObj, "utf8");

    }

    // query: query the db
    public function query($query)
    {
        return self::$dbObj->query($query);
    }

}

/*
    class userLogin
    create user login
*/
class userLogin {

    private $username;
    private $password;

    function __construct($username, $password) {

        $this->_dbConn = new dbHandler();

        $this->username = $username;
        $this->password = $password;

    }

    public function verifyCredentials() {

        if($this->verifyUsername())
        {

        } else {

            exit;

        }

        if($this->verifyPassword())
        {

        } else {

            exit;

        }


    }

    private function verifyUsername() {

        if(!(preg_match('/[^a-z_\-0-9]/i', $this->username)))
        {

            return true;

        }

    }

    private function verifyPassword() {

        $query  = "SELECT * FROM tbl_user";
        $result = $this->_dbConn->query($query);
        $row    = mysql_fetch_assoc($result);

        var_dump($row);
    }

}

我在这里做错了什么？

Answer 1

你所有的包装器都是以mysqli面向对象的方式，突然间你有了这条线？

$row    = mysql_fetch_assoc($result);

您必须使用mysqli结果对象中的fetch_assoc

$result->fetch_assoc()

Answer 2

您的SQL查询显然失败了。为什么你有一个函数查询来调用我不知道的查询，但我感觉这是你的问题的路由原因。你最好用这样的东西：

class dbHandler extends mysqli {

    protected $db_host     = 'localhost';       #db host
    protected $db_username = 'user';  #db username
    protected $db_password = 'password';        #db password
    protected $db_name     = 'db';  #db name

    function __construct()
    {
            parent::__construct($this->db_host, $this->db_username, $this->db_password, $this->db_name);
            if($this->connect_errno)
            {
                    trigger_error('Unable to connect to the database [' . $this->connect_errno . ']: ' . $this->connect_error, E_USER_ERROR);
            }

    }

    public function __destruct()
    {
        parent::close();
    }

}

/*
    class userLogin
    create user login
*/
class userLogin {

    private $username;
    private $password;

    function __construct($username, $password) {

        $this->_dbConn = new dbHandler();

        $this->username = $username;
        $this->password = $password;

    }

    public function verifyCredentials() {

        if($this->verifyUsername())
        {

        } else {

            exit;

        }

        if($this->verifyPassword())
        {

        } else {

            exit;

        }


    }

    private function verifyUsername() {

        if(!(preg_match('/[^a-z_\-0-9]/i', $this->username)))
        {

            return true;

        }

    }

    private function verifyPassword() {

        $query  = "SELECT * FROM tbl_user";
        $result = $this->_dbConn->query($query);
            if($this->_dbConn->errno)
            {
                trigger_error('Error fetching users from table. Query: ' . $query . '. Error: ' . $this->_dbConn->error);
                return false;
            }
            if($result->num_rows)
            {
                while($row = $result->fetch_assoc())
                {
                    var_dump($row);
                }
            }
    }

}

让我知道你是如何继续这样做的。

Answer 3

所以......我从未给过localhost的mysql用户任何授权。仅来自远程LAN。问题解决了。

Answer 4

可能你过早关闭连接？ DBConnect->close();？

因此，如果您在此之后尝试执行任何查询，则会收到错误！

PHP mysqli查询：无法获取mysqli

4 个答案: